BIO Flashcards
(71 cards)
Explain Nitrogen Fixation in the nitrogen cycle
Nitrogen gas (N2) makes up about 78% of the Earth’s atmosphere, but it is in a form that most organisms cannot use directly. Nitrogen-fixing bacteria convert atmospheric
nitrogen into ammonium (NH4+), which is a form of nitrogen that plants can take up and use.
Explain Nitrification in the nitrogen cycle
Ammonium (NH4 + ) can be converted into nitrite (NO 2 - ) and then into nitrate (NO 3 - ) by
nitrifying bacteria. This step is important because nitrate is the primary form of nitrogen taken up
by most plants.
Explain Denitrification in the nitrogen cycle
Denitrifying bacteria convert nitrate (NO 3 - ) and nitrite (NO 2 - ) back into nitrogen gas (N 2 ) or nitrous oxide (N 2 O).
Why is denitrification important?
This process is essential for returning nitrogen to the atmosphere, closing the nitrogen cycle and preventing the accumulation of excess nitrates in the environment, which can have negative environmental impacts.
Explain ammonification in the nitrogen cycle
Microbes, such as bacteria and fungi, break down organic matter, including dead plants and animals, and convert the nitrogen compounds within them into ammonium (NH4+). This makes nitrogen available for reuse by plants.
What is the carbon cycle?
The carbon cycle is the natural process by which carbon moves between the Earth’s atmosphere, oceans, soil, plants, and animals.
Explain decomposition in the Carbon cycle
Microbes are key players in the decomposition of organic matter. During this decomposition process, carbon in the form of organic compounds is converted into carbon dioxide (CO2) and returned to the atmosphere.
Explain photosynthesis in the Carbon cycle
Microscopic photosynthetic organisms, such as phytoplankton in the ocean, capture carbon dioxide from the atmosphere and convert it into organic matter, such as carbohydrates, through photosynthesis.
Explain respiration in the Carbon cycle
Microbes, along with plants and animals, participate in respiration, releasing carbon dioxide back into the atmosphere. During respiration, organic compounds are broken down to produce energy, and carbon is released as CO2.
Explain carbon sequestration in the carbon cycle
Certain microbes (in soil), can contribute to carbon sequestration. They can help stabilise and store organic carbon in the soil, reducing the amount of carbon released into the atmosphere.
Explain methane production and consumption in the carbon cycle
Microbes are involved in the production and consumption of methane (CH4). Methanogenic archaea produce methane in anaerobic environment, while methane-oxidizing bacteria consume it, converting it into CO2.
What was oparin and haldene’s hypothesis / what did the miller-urey experiment prove?
Organic molecules (amino acids) could form from inorganic molecules in earths reducing atmosphere spontaneously - due to high UV and lightning, eventually leading to cells
Cell theory
all living things are made of cells and all cells come from pre-exisiting cells
What are two things needed to be considered to be living
- be made of cells
- carry out life processes
Describe the shape of a eukaryotic cell and its structure
- Round
- Has a membrane-bound nucleus
- Contain membrane-bound organelles
- Larger and more structurally complex
Describe the shape of a prokaryotic cell and its structure
- Skinny
- Lacks a true nucleus
- Lack membrane-bound organelles
- Smaller and less complex
Define Microorganism
an organism that usually can only be seen with a microscope
Explain how microbes are cultured on nutrient agar
- A control dish, kept unopened, checks for sterility.
- Plates are taped partially closed to allow oxygen in, preventing harmful anaerobic bacteria from growing.
- They are sealed to avoid contamination, as they contain millions of microbes after culturing and can cause illness if opened.
- Plates are incubated upside down to prevent condensation from spreading microbes.
- The incubation temperature is kept at or below 25°C to avoid growing human pathogens.
Describe how bacteria reproduce
Binary fission
1. The DNA copies itself
2. The cell membrane pinches the cytoplasm in half
3. Two identical bacterium form
Describe the bacterial structure
Slime capsule that protects the bacteria and prevents it dehydrating.
Cell wall helps to maintain the shape of the bacterium.
Cell membrane that controls the entry and exit of substances in and out of the bacterium.
Cytoplasm where cellular reaction occur.
Genetic material that controls the cellular reactions of the bacterium
Flagellum/a that allows the bacteria to move.
Describe bacteria and fungi nutrition (and where it happens in both bacteria and fungi)
The bacteria secrete enzymes onto their food source.
The enzymes chemically digest the food into smaller molecules outside the bacterium.
The bacteria then absorb the digested food.
Happens in the cell membrane in bacteria and the hyphae for fungi
Describe bacteria and fungi excretion
Bacteria and fungi excrete out the metabolic waste via passive diffusion.
Diffusion involves the process of movement of particles from a site of higher concentration to a site of lower concentration.
The waste material moves out through the cell membrane.
The diffusion of waste material can also occur against the concentration gradient, by active transport which uses energy.
Define respiration
The chemical breakdown of glucose to release energy for life processes
(BACTERIA) Compare anaerobic and aerobic respiration
AEROBIC:
- Oxygen required
- High amount of ATP energy made
- No damaging waste products
ANAEROBIC:
- No oxygen required
- Low amounts of ATP energy made
- Damaging waste product produced
